1. Field of the Invention
The present invention relates to a memory structure and a method of making the memory structure, and more particularly to a flash structure and a method of making the flash structure.
2. Description of the Prior Art
Flash memory is non-volatile computer memory that can be electrically erased and reprogrammed. It is a technology that is primarily used in memory cards and USB flash drives, which are used for general storage and transfer of data between computers and other digital products. As electronic devices become smaller, the size of the flash memory cells is shrinking as well. Today, in order to make the electronic devices with small size, increasing the integration of elements is a major issue.
FIG. 1 shows a structure of a two-bit flash memory cell according to the prior art. As shown in FIG. 1, the structure of the conventional two-bit flash memory cell comprises: a substrate 10, a control gate 12 positioned on the substrate 12, a floating gate 14 positioned at a sidewall of the control gate 12, a spacer 16 positioned on the floating gate 14, a dielectric layer 18 respectively positioned between the control gate 12 and the floating gate 14, and control gate 12 and the spacer 16 as well as on top of the substrate 10, and a gate oxide layer 20 positioned between the control gate 12 and the substrate 10.
The floating gate 14 of the flash memory cell mentioned-above is difficult to fabricate. Furthermore, since the size of the electronic device is shrinking, the short channel effect is formed because the gate channel length becomes short. Therefore, a new structure of the memory cell and a new method of making the memory cell are needed to overcome the short channel effect.